Use dimming ratio when detecting hdr type for local TMO

...otherwise UltraHDR isn't counted as HDR, which then disables
tonemapping to SDR.

Bug: 329464641
Flag: com.android.graphics.surfaceflinger.flags.local_tonemap_screenshots
Test: screenshot Chrome showing an HDR image
Change-Id: I71febc9ef3477938deb4cb904a464f3ab4e598f9